CN112039479B - Film bulk acoustic resonator and manufacturing method thereof - Google Patents
Film bulk acoustic resonator and manufacturing method thereof Download PDFInfo
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- CN112039479B CN112039479B CN201910656067.3A CN201910656067A CN112039479B CN 112039479 B CN112039479 B CN 112039479B CN 201910656067 A CN201910656067 A CN 201910656067A CN 112039479 B CN112039479 B CN 112039479B
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 90
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- 238000000034 method Methods 0.000 claims description 38
- 238000005530 etching Methods 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 22
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 20
- 235000012239 silicon dioxide Nutrition 0.000 claims description 11
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 9
- 239000010703 silicon Substances 0.000 claims description 9
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 7
- 239000010936 titanium Substances 0.000 claims description 7
- 238000001312 dry etching Methods 0.000 claims description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 5
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- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 4
- 230000000149 penetrating effect Effects 0.000 claims description 4
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- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 3
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- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052741 iridium Inorganic materials 0.000 claims description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 2
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 238000005498 polishing Methods 0.000 claims description 2
- 229910052703 rhodium Inorganic materials 0.000 claims description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052707 ruthenium Inorganic materials 0.000 claims description 2
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 2
- 229910052715 tantalum Inorganic materials 0.000 claims description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 239000010937 tungsten Substances 0.000 claims description 2
- NKZSPGSOXYXWQA-UHFFFAOYSA-N dioxido(oxo)titanium;lead(2+) Chemical compound [Pb+2].[O-][Ti]([O-])=O NKZSPGSOXYXWQA-UHFFFAOYSA-N 0.000 claims 1
- 239000011787 zinc oxide Substances 0.000 claims 1
- 239000010408 film Substances 0.000 description 21
- 230000008569 process Effects 0.000 description 18
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- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 description 8
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- 235000012431 wafers Nutrition 0.000 description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
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- GPXJNWSHGFTCBW-UHFFFAOYSA-N Indium phosphide Chemical compound [In]#P GPXJNWSHGFTCBW-UHFFFAOYSA-N 0.000 description 2
- AXQKVSDUCKWEKE-UHFFFAOYSA-N [C].[Ge].[Si] Chemical compound [C].[Ge].[Si] AXQKVSDUCKWEKE-UHFFFAOYSA-N 0.000 description 2
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
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- 239000011572 manganese Substances 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 238000000231 atomic layer deposition Methods 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
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- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- UKDIAJWKFXFVFG-UHFFFAOYSA-N potassium;oxido(dioxo)niobium Chemical compound [K+].[O-][Nb](=O)=O UKDIAJWKFXFVFG-UHFFFAOYSA-N 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- -1 scandium (Sc) Chemical class 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/10—Mounting in enclosures
- H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
- H03H9/1035—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/10—Mounting in enclosures
- H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
- H03H9/105—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a cover cap mounted on an element forming part of the BAW device
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
- H03H9/02031—Characteristics of piezoelectric layers, e.g. cutting angles consisting of ceramic
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
- H03H9/02118—Means for compensation or elimination of undesirable effects of lateral leakage between adjacent resonators
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/132—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials characterized by a particular shape
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/173—Air-gaps
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/176—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator consisting of ceramic material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/021—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the air-gap type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
Abstract
The invention discloses a film bulk acoustic resonator and a manufacturing method thereof, wherein the film bulk acoustic resonator comprises: a first substrate; a support layer bonded to the first substrate; a first cavity formed in the support layer; a piezoelectric stack structure on the support layer; a first trench and a second trench formed in the piezoelectric stack structure; a dielectric layer on the piezoelectric stack; a second cavity formed in the dielectric layer; the first groove is communicated with the first cavity, the second groove is communicated with the second cavity, and the second substrate of the second cavity is covered. The groove structure effectively blocks transverse waves from being transmitted from the effective working area, improves acoustic loss, improves the quality factor of the film bulk acoustic resonator, and simultaneously effectively solves the problem that all layers exposed in the upper space are free from pollution of external environment, and integrally improves the performance of the device.
Description
Technical Field
The invention relates to the field of semiconductor device manufacturing, in particular to a film bulk acoustic resonator and a manufacturing method thereof.
Background
Since the development of analog rf communication technology in the beginning of the last 90 th generation, rf front-end modules have gradually become the core components of communication devices. Among all the radio frequency front end modules, the filter has become the most powerful component of growth and development prospect. With the rapid development of wireless communication technology, the 5G communication protocol is mature, and the market also puts forward more strict standards on the performance of the radio frequency filter in all aspects. The performance of the filter is determined by the resonator elements that make up the filter. Among the existing filters, a Film Bulk Acoustic Resonator (FBAR) is one of the most suitable filters for 5G applications due to its small size, low insertion loss, large out-of-band rejection, high quality factor, high operating frequency, large power capacity, and good antistatic impact capability.
In general, a thin film bulk acoustic resonator includes two thin film electrodes, and a piezoelectric thin film layer is disposed between the two thin film electrodes, and the working principle of the thin film bulk acoustic resonator is that the piezoelectric thin film layer is utilized to generate vibration under an alternating electric field, the vibration excites bulk acoustic waves propagating along the thickness direction of the piezoelectric thin film layer, and the acoustic waves are transmitted to the interface between the upper electrode and the lower electrode and air to be reflected back, and then are reflected back and forth inside the thin film to form oscillation. Standing wave oscillation is formed when the acoustic wave propagates in the piezoelectric film layer just an odd multiple of half the wavelength.
However, the cavity type thin film bulk acoustic resonator manufactured at present has a transverse wave loss, and the quality factor (Q) cannot be further improved, so that the requirement of a high-performance radio frequency system cannot be met.
Disclosure of Invention
The invention aims to provide a film bulk acoustic resonator and a manufacturing method thereof, which can improve the transverse wave loss of the resonator, improve the quality factor of the film bulk acoustic resonator, protect the resonator from external environment pollution and improve the performance of the device as a whole, and the invention aims to realize the purposes that the film bulk acoustic resonator comprises:
a first substrate;
a support layer bonded to the first substrate, the support layer having a first cavity formed therein that extends through the support layer;
a piezoelectric stack structure covering the first cavity, the piezoelectric stack structure including a first electrode, a piezoelectric layer, and a second electrode laminated in sequence;
a dielectric layer which is grown above the piezoelectric laminated structure, wherein a second cavity penetrating through the dielectric layer is formed in the dielectric layer, and the second cavity is positioned above the first cavity; a second substrate bonded to the dielectric layer and covering the second cavity;
the first groove is formed on the piezoelectric laminated structure between the first cavity and the second cavity, penetrates through the first electrode and the piezoelectric layer, is communicated with the first cavity, an area surrounded by the first groove and the second groove is an effective working area of the resonator, and the first groove and the second groove are connected or provided with a gap at two junctions of projection of the bottom surface of the first substrate;
the second groove is formed on the piezoelectric laminated structure between the first cavity and the second cavity, penetrates through the second electrode and the piezoelectric layer, and is communicated with the second cavity, and the projection of the area surrounded by the first groove and the second groove on the vertical plane forms a closed or nearly closed graph.
Alternatively, the cross section of the effective working area is polygonal, and any two sides of the polygon are not parallel.
Alternatively, the inclination angle between the side wall of the first groove and the plane where the second electrode is located is greater than 90 degrees; the inclination angle of the side wall of the second groove and the plane where the first electrode is located is larger than 90 degrees.
The invention also provides a manufacturing method of the film bulk acoustic resonator, which comprises the following steps:
providing a third substrate;
forming a piezoelectric laminated structure on the third substrate, wherein the piezoelectric laminated structure comprises a second electrode layer, a piezoelectric layer and a first electrode layer which are sequentially formed on the third substrate;
forming a support layer on the piezoelectric stack structure;
forming a first cavity in the support layer, wherein the first cavity penetrates through the support layer;
forming a first groove at the bottom of the first cavity, wherein the first groove penetrates through the first electrode layer and the piezoelectric layer;
bonding the first substrate on the support layer, wherein the first substrate covers the first cavity;
removing the third substrate, and forming a dielectric layer on the exposed surface;
forming a second cavity on the dielectric layer, wherein the second cavity penetrates through the dielectric layer, and the second cavity is positioned above the first cavity;
forming a second groove at the bottom of the second cavity, wherein the second groove is positioned above the first cavity and penetrates through the second electrode layer and the piezoelectric layer, the area surrounded by the first groove and the second groove is an effective working area of the resonator, and the first groove and the second groove are connected or provided with a gap at two junctions of projection of the bottom surface of the first substrate;
and bonding a second substrate on the dielectric layer, wherein the second substrate covers the second cavity.
Alternatively, the shape of the effective working area of the resonator is a polygon, and any two sides of the polygon are not parallel.
Alternatively, the inclination angle between the side wall of the first groove and the plane where the second electrode is located is greater than 90 degrees; the inclination angle of the side wall of the second groove and the plane where the first electrode is located is larger than 90 degrees.
In summary, the thin film bulk acoustic resonator provided by the invention includes an upper cavity, a lower cavity, a piezoelectric lamination structure between the upper cavity and the lower cavity, and a first groove and a second groove on the piezoelectric lamination structure in the cavity, wherein an area surrounded by the first groove and the second groove is an effective working area of the thin film bulk acoustic resonator. According to the invention, the boundary between the piezoelectric layer and the second electrode is exposed in the air by the first groove, the piezoelectric layer material and the electrode material have larger impedance mismatch with the air, so that parasitic transverse waves in the piezoelectric laminated structure are reflected at an air interface, the energy leakage of the transverse waves is prevented, and the energy leakage of the transverse waves is prevented by the second groove. Therefore, the invention improves the acoustic wave loss, and improves the quality factor of the film bulk acoustic resonator, thereby improving the device performance. Meanwhile, the invention also provides a manufacturing method of the film bulk acoustic resonator, which is compatible with the main process of the resonator, has simple flow and effectively protects the resonance area.
Furthermore, because the effective working area is an irregular polygon, the transverse wave reflected from the first groove and the air interface and the transverse wave reflected from the first groove and the air interface can not generate additional standing wave oscillation, the acoustic wave loss is further improved, the quality factor of the film bulk acoustic resonator is improved, and the device performance is further improved.
The invention has other features and advantages which will be apparent from or are set forth in detail in the accompanying drawings and the following detailed description, which are incorporated herein, taken in conjunction with the accompanying drawings and the detailed description, which illustrate certain principles of the invention.
Drawings
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the invention.
FIG. 1A is a schematic cross-sectional view of a thin film bulk acoustic resonator according to an embodiment of the present invention;
FIG. 2A is a top view of one embodiment of FIG. 1A;
FIG. 2B is a top view of another embodiment of FIG. 1A;
FIG. 3 is a flowchart of a method for fabricating a thin film bulk acoustic resonator according to the present invention;
fig. 4 to 14 are schematic structural diagrams corresponding to corresponding steps of a method for manufacturing a thin film bulk acoustic resonator according to this embodiment.
Reference numerals illustrate:
100-a first substrate; 200-a second substrate; 300-a third substrate; 120-piezoelectric stack structure; 130-trench structure; 101-a support layer; 110a' -a first opening; 110b' -a second opening; 110 a-a first cavity; 110 b-a second cavity; 130 a-a first trench; 130 b-a second trench; 103-first electrode/first electrode layer (first electrode layer patterned to form first electrode); 103 a-a first electrode edge region; 1032—a first electrode resonance region; 104-a piezoelectric layer; 1042-a piezoelectric resonance region; 105-second electrode/second electrode layer (second electrode layer patterned to form second electrode); 105 a-a second electrode edge region; 1052-a second electrode resonance region; 106-a dielectric layer; 107 a-first pads; 107 a-second pads; 150 a-first junction; 150 b-second junction; 150a' -a first junction opening; 150b' -second junction opening; 001-active working area.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. While alternative embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The film bulk acoustic resonator and the method of manufacturing the film bulk acoustic resonator according to the present invention will be described in further detail with reference to the accompanying drawings and specific examples. The advantages and features of the present invention will become more apparent from the following description and drawings, however, it should be understood that the inventive concept may be embodied in many different forms and is not limited to the specific embodiments set forth herein. The drawings are in a very simplified form and are to non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.
The terms "first," "second," and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention herein are, for example, capable of operation in other sequences than described or illustrated herein. Similarly, if a method herein comprises a series of steps, and the order of the steps presented herein is not necessarily the only order in which the steps may be performed, and some steps may be omitted and/or some other steps not described herein may be added to the method. If a component in one drawing is identical to a component in another drawing, the component will be easily recognized in all drawings, but in order to make the description of the drawings clearer, the specification does not refer to all the identical components in each drawing.
An embodiment of the present invention provides a thin film bulk acoustic resonator, please refer to fig. 1A, fig. 1A is a schematic cross-sectional structure diagram of the thin film bulk acoustic resonator according to an embodiment of the present invention, including: a first substrate 100; a support layer 101 on the first substrate 100, the support layer 101 being bonded to the first substrate 100; a first cavity 110a formed in the support layer 101; a piezoelectric stack 120 (including a first electrode 130, a piezoelectric layer 140, a second electrode 150) covering the first cavity 110a; a first trench 130a and a second trench 130b formed in the piezoelectric stack structure 120, wherein the first trench 130a penetrates the first electrode 130 and the piezoelectric layer 140, and the second trench 130b penetrates the second electrode 150 and the piezoelectric layer 140; a dielectric layer 106 formed on the piezoelectric stack 120; a second cavity 110b formed in the dielectric layer 106 and penetrating the dielectric layer 106, the second cavity 110b being located above the first cavity 110a; wherein the first groove 130a is communicated with the first cavity 110a, the second groove 130b is communicated with the second cavity 110b, and the projection of the area surrounded by the first groove 130a and the second groove 130b on the vertical plane forms a closed or nearly closed graph; a second substrate 200 covering the second cavity 110b.
As known from the working principle of the film bulk acoustic resonator, the working area of the film bulk acoustic resonator is an area where the first electrode 103, the piezoelectric layer 104 and the second electrode 105 overlap at the same time, and the effective working area in the present invention is an inner area surrounded by the first trench 130a and the second trench 130b.
In an embodiment, the area enclosed by the first trench 130a and the second trench 130b is a closed pentagon, and the connection portion is a first connection portion 150a and a second connection portion 150b, please refer to fig. 2A, fig. 2A is a top view of a film bulk acoustic resonator according to an embodiment of the present invention. In another embodiment, the area enclosed by the first trench 130a and the second trench 130B is a nearly closed pentagon, the joint opening is a first joint opening 150a 'and a second joint opening 150B', please refer to fig. 2B, and fig. 2B is a top view of a film bulk acoustic resonator according to another embodiment of the present invention.
The first groove in this embodiment communicates with the first cavity and the second groove communicates with the second cavity. The area surrounded by the first groove and the second groove is an effective working area, and further, as the effective working area is an irregular polygon, the transverse wave reflected back from the first groove and the air interface and the transverse wave reflected back from the second groove and the air interface can not generate additional standing wave oscillation, the acoustic wave loss is further improved, the quality factor of the film bulk acoustic resonator is improved, and the device performance is further improved. Meanwhile, the film bulk acoustic resonator with the upper packaging cover structure effectively solves the problem that all layers exposed in the upper space are free from external environment pollution, and the performance of the device is improved as a whole.
The first substrate 100 may be any suitable substrate known to those skilled in the art, and may be, for example, at least one of the materials mentioned below: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III/V compound semiconductors, and also include multilayer structures composed of these semiconductors, or the like, or are silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon-on-insulator (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), or may be double-sided polished silicon wafers (Double Side Polished Wafers, DSP), or may be ceramic substrates such as alumina, quartz, or glass substrates, or the like. The first substrate 100 in this embodiment is P-type high-resistance monocrystalline silicon with a crystal orientation. The material of the support layer 101 may be any suitable dielectric material including, but not limited to, at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, and the like.
The support layer 101 is disposed on the first substrate 100, and a first cavity 110a is disposed in the support layer 101, and the first cavity 110a may be formed by etching the support layer 101 through an etching process. The technique of the present invention is not limited thereto. In the present embodiment, the bottom surface of the first cavity 110a is rectangular, but in other embodiments of the present invention, the bottom surface of the first cavity 110a may be circular, elliptical, or polygonal other than rectangular, such as pentagonal, hexagonal, etc. The first cavity 110a is not limited to be formed in the support layer 101, and the first cavity 110a may be formed directly in the first substrate 100 without providing the support layer 101, and the piezoelectric stack structure 120 may be directly disposed on the first substrate 100.
The piezoelectric stack 120 includes a first electrode 103, a piezoelectric layer 104, and a second electrode 105, the first electrode 103 being located on the support layer 101. The piezoelectric layer 104 is located on the first electrode 103, the second electrode 105 is located on the piezoelectric layer 104, and an overlapping region of the first electrode 103, the piezoelectric layer 104, and the second electrode 105 in the thickness direction is directly above the first cavity 110a. An etch stop layer 102 is further disposed between the first support layer 101 and the first electrode 103, and the material of the etch stop layer includes, but is not limited to, silicon nitride (Si 3N 4) and silicon oxynitride (SiON). The etching stop layer 102 may be used to increase structural stability of the finally manufactured thin film bulk acoustic resonator, on the one hand, and on the other hand, the etching stop layer 102 has a lower etching rate than the supporting layer 101, and may prevent over etching during the process of etching the supporting layer 101 to form the first cavity 110a, and protect the surface of the first electrode 103 located thereunder from being damaged, thereby improving device performance and reliability. The first electrode 103 includes an edge region 103a not covered with the piezoelectric layer 104 and the second electrode 105, so as to facilitate input/output of subsequent electric signals.
Dielectric layer 106 on second electrode 105 and second substrate 200 on dielectric layer 106. The dielectric layer 106 has a second cavity 110b formed therein, the second cavity 110b being disposed opposite the first cavity 110a, the second cavity 110b being formed by etching the dielectric layer 106. In the present embodiment, the bottom surface of the second cavity 110b is rectangular, but in other embodiments of the present invention, the bottom surface of the second cavity 110b may be circular, elliptical, or polygonal other than rectangular, such as pentagonal, hexagonal, etc. In this embodiment, the second cavity 110b and the first cavity 110a are disposed on the upper and lower sides of the piezoelectric stack structure 120, respectively, and optionally, the second cavity 110b and the first cavity 110a are symmetrically disposed with respect to the piezoelectric stack structure 120. The material of the second substrate 200 may be the same as that of the first substrate 100, or may be any other suitable substrate known to those skilled in the art. The second electrode 105 includes an edge region 105a not covered by the dielectric layer 106, so as to facilitate input/output of subsequent electrical signals.
A Trench (Air Trench) structure, which may also be referred to as an Air gap cavity (Air Trench), is disposed in the piezoelectric stack structure 120, and includes a first Trench 130a and a second Trench 130b, the first Trench 130a extending through the first electrode 103 and the piezoelectric layer 104 and communicating with the first cavity 110a, and the second Trench 130b extending through the second electrode 105 and the piezoelectric layer 104 and communicating with the second cavity 110b. Referring to fig. 2A, the projections of the first trench 130a and the second trench 130b on the plane of the piezoelectric layer 104 are semi-annular or polygonal similar to semi-annular, and the projections of the first trench 130a and the second trench 130b on the plane of the piezoelectric layer 104 may be just connected or nearly connected, i.e. the projections of the first trench 130a and the second trench 130b on the plane of the piezoelectric layer 104 may form a completely closed ring or nearly closed ring, where the connection point of the projections of the first trench 130a and the second trench 130b on the plane of the piezoelectric layer 104 includes: a first junction 150a and a second junction 150b. The first groove 130a and the second groove 130b cooperate to block transverse waves around the piezoelectric resonance region 1042, that is, the region where the pattern (circular or polygonal) enclosed by the projections of the first groove 130a and the second groove 130b on the plane where the piezoelectric layer 104 is located is the effective working region 001 of the thin film bulk acoustic resonator. The first groove 130a and the second groove 130b are located at the periphery of the effective working area 001, and the projection sizes of the first groove 130a and the second groove 130b on the plane where the piezoelectric layer 104 is located may be equal to the ring formed by combining the two (at this time, the first groove 130a and the second groove 130b are located on two sides of the effective working area 001 and all the parts are completely opposite), or may not be equal (at this time, the first groove 130a and the second groove 130b are located on two sides of the effective working area 001 and only part of the parts are opposite).
Referring to fig. 13, in the piezoelectric stack structure 120, the first electrode 103 includes a first electrode resonance region 1032, and the first electrode resonance region 1032 overlaps the effective operation region 001. The second electrode 105 includes a second electrode resonant region 1052, and the second electrode resonant region 1052 overlaps with the effective operating region 001. The piezoelectric layer 104 includes a piezoelectric resonance region 1042, and the piezoelectric resonance region 1042 is located between the first electrode resonance region 1032 and the second electrode resonance region 1052, that is, overlaps the effective operation region 001. The overlapping region of the second cavity 110b and the first cavity 110a in the thickness direction covers the first trench 130a, the second trench 130b, and the effective working region 001 (i.e., the first electrode resonance region 1032, the second electrode resonance region 1052, and the piezoelectric resonance region 1042).
In other embodiments of the present invention, the thin film bulk acoustic resonator further comprises: signal input/output structure. Referring to fig. 2B and 14, for example, the signal input/output structure is a first pad 107a and a second pad 107B respectively connecting the first electrode 103 and the second electrode 105, specifically, the first pad 107a is connected to an edge region 103a of the first electrode 103 which is not covered with the piezoelectric layer 104 and the second electrode 105, and the second pad 107B is connected to an edge region 105a of the second electrode 105 which is not covered with the dielectric layer 106.
The present invention also provides a method for manufacturing a thin film bulk acoustic resonator, and fig. 3 is a flowchart of a method for manufacturing a thin film bulk acoustic resonator according to the present invention, please refer to fig. 3, which includes:
s01: providing a third substrate; forming a piezoelectric laminated structure on a third substrate, wherein the piezoelectric laminated structure comprises a second electrode layer, a piezoelectric layer and a first electrode layer which are sequentially formed on the third substrate;
s02: forming a support layer on the piezoelectric stack structure; forming a first cavity in the supporting layer, wherein the first cavity penetrates through the supporting layer; forming a first groove at the bottom of the first cavity, wherein the first groove penetrates through the first electrode layer and the piezoelectric layer;
s03: bonding a first substrate on the support layer, wherein the first substrate covers the first cavity;
s04: removing the third substrate to expose the second electrode layer;
s05: forming a dielectric layer on the second electrode layer; forming a second cavity on the dielectric layer, wherein the second cavity penetrates through the dielectric layer, and the second cavity is positioned above the first cavity; forming a second groove at the bottom of the second cavity, wherein the second groove penetrates through the second electrode layer and the piezoelectric layer;
s06: and bonding a second substrate on the dielectric layer, wherein the second substrate covers the second cavity.
Fig. 4 to 14 are schematic structural diagrams corresponding to the steps of a method for manufacturing a thin film bulk acoustic resonator according to the present embodiment, and the method for manufacturing a thin film bulk acoustic resonator according to the present embodiment will be described in detail below.
Referring to fig. 4 and 5, step S01 is performed to provide a third substrate 300, and the piezoelectric stack structure 120 is formed on the third substrate 300. The piezoelectric stack structure 120 includes a second electrode layer 105, a piezoelectric layer 104, and a first electrode layer 103, wherein the piezoelectric layer 104 is located between the first electrode layer 103 and the second electrode layer 105, and the first electrode layer 103 and the second electrode layer 105 are disposed opposite to each other. The first electrode layer 103 and the second electrode layer 105 are patterned to form the first electrode 103 and the second electrode 105, and the first electrode 103 may be used as an input electrode or an output electrode that receives or provides an electrical signal such as a Radio Frequency (RF) signal. For example, when the second electrode 105 is used as an input electrode, the first electrode 103 may be used as an output electrode, and when the second electrode 105 is used as an output electrode, the first electrode 103 may be used as an input electrode, and the piezoelectric layer 104 converts an electric signal input through the first electrode 103 or the second electrode 105 into a bulk acoustic wave. For example, the piezoelectric layer 104 converts an electrical signal into a bulk acoustic wave by physical vibration.
An isolation layer (not shown in fig. 5) is also formed between the third substrate 300 and the second electrode 105 layer. In the subsequent lift-off process, the third substrate 300 can be separated from the subsequently formed piezoelectric stack structure 120 by etching the isolation layer, which is conducive to rapid lift-off of the third substrate 300 and improvement of process manufacturing efficiency. The isolation layer is made of at least one of silicon dioxide (SiO 2), silicon nitride (Si 3N 4), aluminum oxide (Al 2O 3) and aluminum nitride (AlN). The isolation layer can be formed by chemical vapor deposition, magnetron sputtering or evaporation and the like. In this embodiment, the third substrate 300 is monocrystalline silicon, and the isolation layer is made of silicon dioxide (SiO 2).
The materials of the second electrode layer 105 and the first electrode layer 103 may be any suitable conductive material or semiconductor material known to those skilled in the art, wherein the conductive material may be a metal material having conductive properties, for example, one of molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), or a laminate formed of the above metals, and the semiconductor material is Si, ge, siGe, siC, siGeC, or the like. The second electrode 105 layer and the first electrode 103 layer may be formed by physical vapor deposition such as magnetron sputtering, evaporation, or a chemical vapor deposition method. As a material of the piezoelectric layer 104, a piezoelectric material having a wurtzite crystal structure such as aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO 3), quartz (Quartz), potassium niobate (KNbO 3), or lithium tantalate (LiTaO 3), or a combination thereof can be used. When the piezoelectric layer 104 includes aluminum nitride (AlN), the piezoelectric layer 104 may further include at least one of rare earth metals, such as scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). In addition, when the piezoelectric layer 104 includes aluminum nitride (AlN), the piezoelectric layer 104 may further include at least one of transition metals such as zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). The piezoelectric layer 104 may be deposited using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition. Alternatively, in the present embodiment, the second electrode layer 105 and the first electrode layer 103 are made of metallic molybdenum (Mo), and the piezoelectric layer 104 is made of aluminum nitride (AlN).
The shapes of the second electrode 105, the piezoelectric layer 104, and the first electrode 103 may be the same or different, and the areas of the second electrode 105, the piezoelectric layer 104, and the first electrode 103 may be the same or different. Before forming the second electrode layer 105, a seed layer (not shown in fig. 5) may be formed on the isolation layer, where the seed layer is formed between the isolation layer and the second electrode layer 105, and has a direction to the crystal direction of the subsequently formed second electrode layer 105 (the piezoelectric layer 104 and the first electrode layer 103), so that the subsequently formed piezoelectric stack structure 120 is grown along a specific crystal direction, and uniformity of the piezoelectric layer 104 is ensured. The seed layer may be made of aluminum nitride (AlN), and may be formed of a metal or a dielectric material having a hexagonal close-packed (HCP) structure other than AlN. For example, the seed layer may also be formed of metallic titanium (Ti).
Referring to fig. 6 to 9, step S02 is performed to form a support layer 101 on the first electrode layer 103; etching the support layer 101 to form a first cavity 110a; the first electrode layer 103 and the piezoelectric layer 104 are etched in the first cavity 110a to form a first trench 130a, the first trench 130a communicating with the first cavity 110a. The first substrate 100 is bonded on the support layer 101. Specifically, as shown in fig. 6, first, the support layer 101 may be formed on the first electrode layer 103 by a chemical deposition method, and the material of the support layer 101 may be, for example, one or a combination of several of silicon dioxide (SiO 2), silicon nitride (Si 3N 4), aluminum oxide (Al 2O 3), and aluminum nitride (AlN). In this embodiment, the material of the supporting layer 101 is silicon dioxide (SiO 2). Then, as shown in fig. 7, the first opening 110a' is formed to expose a portion of the first electrode layer 103 by etching the support layer 101 through an etching process, which may be a wet etching process or a dry etching process, wherein the dry etching process is preferably used, and the dry etching process includes, but is not limited to, reactive Ion Etching (RIE), ion beam etching, plasma etching, or laser cutting. The depth and shape of the first opening 110a 'are both dependent on the depth and shape of the cavity required for the bulk acoustic resonator to be manufactured, i.e. the depth of the first opening 110a' can be determined by forming the thickness of the support layer 101. The bottom surface of the first opening 110a' may have a rectangular shape or a polygonal shape other than a rectangular shape, such as pentagonal, hexagonal, octagonal, etc., and may have a circular shape or an elliptical shape. In other embodiments of the present invention, the longitudinal cross-sectional shape of the first opening 110a' may also be a spherical cap with a wider upper portion and a narrower lower portion, i.e., a U-shaped longitudinal cross-section.
In this embodiment, before forming the supporting layer 101, an etching stop layer 102 is further formed on the first electrode 103, and the material of the etching stop layer includes, but is not limited to, silicon nitride (Si 3N 4) and silicon oxynitride (SiON). The etching stop layer 102 has a lower etching rate than the support layer 101 formed later, and can prevent over etching when the support layer 101 is etched later to form the first opening 110a', thereby protecting the surface of the first electrode 103 located thereunder from damage.
Next, the first electrode layer 103 and the piezoelectric layer 104 are etched to form a first trench 130a within the first opening 110a', as shown in fig. 8. The sidewalls of the first trench 130a may be inclined or vertical. In this embodiment, the sidewall of the first trench 130a and the plane of the second electrode layer 105 form an obtuse angle (the longitudinal cross section (cross section along the thickness direction of the substrate) of the first trench 130a is inverted trapezoid). The first trench 130a is projected as a semi-ring or a semi-ring-like polygon on the plane of the piezoelectric layer 104.
Step S03 is performed to bond the first substrate 100 with the support layer 101, and the first substrate 100 and the first electrode layer 103 form a first cavity 110a at the first opening 110a' of the support layer 101. The first substrate 100 may be any suitable substrate known to those skilled in the art, and may be, for example, at least one of the materials mentioned below: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III/V compound semiconductors, and also include multilayer structures composed of these semiconductors, or the like, or are silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon-on-insulator (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), or may be double-sided polished silicon wafers (Double Side Polished Wafers, DSP), or may be ceramic substrates such as alumina, quartz, or glass substrates, or the like. Bonding of the first substrate 100 to the support layer 101 may be achieved by thermal compression bonding, or bonding of the first substrate 100 to the support layer 101 may be achieved by dry film bonding.
In other embodiments of the present invention, the forming method of the first trench 130a and the first opening 110a' further includes:
providing a first substrate 100, forming a support layer 101 on the first substrate 100, etching the support layer 101 to expose a portion of the first substrate 100, and forming a first opening 110a' in the support layer 101;
etching the first electrode layer 103 and the piezoelectric layer 104 to form a first trench 130a;
the support layer 101 formed with the first opening 110a' is bonded with the piezoelectric stack structure 120 formed with the first trench 130 a.
The process steps for fabricating the first trench 130a and the support layer 101 having the first opening 110a' are not limited in time, and may be performed according to actual process conditions by those skilled in the art.
After the bonding process is completed, step S04 is performed to remove the third substrate 200, and the bonded thin film bulk acoustic resonator is flipped over, so as to obtain the structure shown in fig. 10. The third substrate 300 is peeled off in this embodiment by etching an isolation layer (not shown). In other embodiments of the present invention, the third substrate 300 may be removed by other means, such as etching or mechanical polishing.
Referring to fig. 11 to 13, step S05 is performed to etch the second electrode layer 105 and the piezoelectric layer 104 to form the second trench 130b, and projections of the first trench 130a and the second trench 130b on the plane of the piezoelectric layer 104 enclose a closed or nearly closed pattern.
Specifically, first, the dielectric layer 106 may be formed on the second electrode layer 105 by a chemical deposition method, and as shown in fig. 11, the dielectric layer 106 and the support layer 101 are made of the same material, for example, one or a combination of several of silicon dioxide (SiO 2), silicon nitride (Si 3N 4), aluminum oxide (Al 2O 3) and aluminum nitride (AlN). In this embodiment, the material of the dielectric layer 106 is silicon dioxide (SiO 2).
Then, as shown in fig. 12, the dielectric layer 106 is etched by an etching process, which may be a wet etching process or a dry etching process, including, but not limited to, reactive Ion Etching (RIE), ion beam etching, plasma etching, or laser cutting, to expose a portion of the second electrode layer 105. The depth and shape of the second opening 110b 'are dependent on the depth and shape of the cavity required for the bulk acoustic resonator to be manufactured, i.e. the depth of the second opening 110b' can be determined by forming the thickness of the dielectric layer 106. The bottom surface of the second opening 110b' may have a rectangular shape or a polygonal shape other than a rectangular shape, such as pentagonal, hexagonal, octagonal, etc., and may have a circular shape or an elliptical shape. In other embodiments of the present invention, the longitudinal cross-sectional shape of the second opening 110b' may also be a spherical cap with a wider upper portion and a narrower lower portion, i.e., a U-shaped longitudinal cross-section. Next, as shown in fig. 13, the second electrode layer 105 and the piezoelectric layer 104 are etched to form a second trench 130b within the second opening 110 b'. The sidewalls of the second trench 130b may be inclined or vertical. In this embodiment, the sidewall of the second trench 130b and the plane of the first electrode layer 103 form an obtuse angle (the longitudinal cross section (cross section along the thickness direction of the substrate) of the second trench 130b is inverted trapezoid). The second trench 130b is projected as a semi-ring or a polygon like a semi-ring on the plane of the piezoelectric layer 104.
As shown in fig. 2A and 2B, the projections of the first trench 130a and the second trench 130B on the plane of the piezoelectric layer 104 are semi-annular or polygonal similar to semi-annular, and the projections of the first trench 130a and the second trench 130B on the plane of the piezoelectric layer 104 may just meet or be close to meet, i.e. the projections of the first trench 130a and the second trench 130B on the plane of the piezoelectric layer 104 may form a completely closed loop or a close to closed loop, where the joint of the projections of the first trench 130a and the second trench 130B on the plane of the piezoelectric layer 104 includes: a first junction 150a and a second junction 150b. The first groove 130a and the second groove 130b cooperate to block transverse waves around the piezoelectric resonance region 1042, that is, the region where the pattern (circular or polygonal) enclosed by the projections of the first groove 130a and the second groove 130b on the plane where the piezoelectric layer 104 is located is the effective working region 001 of the thin film bulk acoustic resonator. The first groove 130a and the second groove 130b are located at the periphery of the effective working area 001, and the projection sizes of the first groove 130a and the second groove 130b on the plane where the piezoelectric layer 104 is located may be equal to the ring formed by combining the two (at this time, the first groove 130a and the second groove 130b are located on two sides of the effective working area 001 and all the parts are completely opposite), or may not be equal (at this time, the first groove 130a and the second groove 130b are located on two sides of the effective working area 001 and only part of the parts are opposite).
In this embodiment, the pattern (effective working area 001) enclosed by the projections of the first trench 130a and the second trench 130b on the plane where the piezoelectric layer 104 is located is a pentagon that just meets, and any two sides of the polygon are not parallel. In other embodiments of the present invention, the pattern formed by the projections of the first and second grooves 130a and 130B on the plane of the piezoelectric layer 104 may also be a nearly closed pentagon with openings (the first and second openings 150a 'and 150B') at two junctions, as shown in fig. 2B.
In this embodiment, during the process of etching the dielectric layer 106 to form the second opening 110b', a portion of the dielectric layer 106 may be etched to expose the edge portion 105a of the second electrode layer 105, so that signal input/output of the second electrode layer 105 may be facilitated, for example, the second pad 107b may be formed on the edge portion 105 a. In addition, in the process of etching the second electrode layer 105 and the piezoelectric layer 104 to form the second trench 130b, portions of the second electrode layer 105 (edge portion 105 a) and the piezoelectric layer 104 may be etched to expose the edge portion 103a of the first electrode 103 layer side, so that signal input/output of the first electrode layer 103 may be facilitated, for example, the first pad 107a may be formed on the edge portion 103 a.
Finally, referring to fig. 14, step S06 is performed to provide a second substrate 200, and the dielectric layer 106 is bonded to the second substrate 200 to form a second cavity 110b at the second opening 110b' of the dielectric layer 106. The second substrate 200 may be any suitable substrate known to those skilled in the art. In this embodiment, the material of the second substrate 200 is P-type high-resistance monocrystalline silicon. Bonding of the second substrate 200 to the dielectric layer 106 may be achieved by thermal compression bonding, or bonding of the second substrate 200 to the dielectric layer 106 may be achieved by dry film bonding.
In other embodiments of the present invention, the forming method of the second trench 130b and the second cavity further includes:
etching the second electrode layer 105 and the piezoelectric layer 104 to form a second trench 130b within the second opening 110b';
providing a second substrate 200, forming a dielectric layer 106 on the second substrate 200, etching the dielectric layer 106 to expose a portion of the second substrate 200, and forming a second opening 110b' in the dielectric layer 106;
the dielectric layer 106 formed with the second opening 110b' is bonded with the piezoelectric stack 120 formed with the second trench 130b.
The process steps for fabricating the second trench 130b and the dielectric layer 106 having the second opening 110b' are not limited in time, and may be performed according to actual process conditions by those skilled in the art.
It should be noted that, in the present specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment is mainly described in a different point from other embodiments. In particular, for structural embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and reference is made to the description of method embodiments for relevant points.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described.
Claims (16)
1. A thin film bulk acoustic resonator, comprising:
a first substrate;
a support layer bonded to the first substrate, the support layer having a first cavity formed therein that extends through the support layer;
a piezoelectric stack structure covering the first cavity, the piezoelectric stack structure including a first electrode, a piezoelectric layer, and a second electrode laminated in sequence;
a dielectric layer which is grown above the piezoelectric laminated structure, wherein a second cavity penetrating through the dielectric layer is formed in the dielectric layer, and the second cavity is positioned above the first cavity;
a second substrate bonded to the dielectric layer and covering the second cavity;
a first groove formed on the piezoelectric laminated structure between the first cavity and the second cavity and penetrating through the first electrode and the piezoelectric layer, wherein the first groove is communicated with the first cavity;
the second groove is formed on the piezoelectric laminated structure between the first cavity and the second cavity, penetrates through the second electrode and the piezoelectric layer, is communicated with the second cavity, an area surrounded by the first groove and the second groove is an effective working area of the resonator, and the first groove and the second groove are connected or provided with a gap at two juncture of projection of the bottom surface of the first substrate.
2. The thin film bulk acoustic resonator of claim 1, wherein the cross-section of the active region is polygonal in shape and any two sides of the polygon are non-parallel.
3. The thin film bulk acoustic resonator of claim 1, wherein a sidewall of the first trench is inclined at an angle greater than 90 degrees to a plane in which the second electrode is located; the inclination angle of the side wall of the second groove and the plane where the first electrode is located is larger than 90 degrees.
4. The thin film bulk acoustic resonator of claim 1, further comprising an insulating layer disposed between the first electrode and the support layer.
5. The thin film bulk acoustic resonator of claim 4, wherein the insulating layer material comprises silicon oxide or silicon nitride.
6. The thin film bulk acoustic resonator of claim 1, wherein the material of the piezoelectric layer comprises aluminum nitride, zinc oxide, lead zirconate titanate, or lead titanate.
7. The thin film bulk acoustic resonator of claim 1, wherein the material of the support layer or the dielectric layer comprises one or a combination of several of silicon dioxide, silicon nitride, aluminum oxide and aluminum nitride.
8. The thin film bulk acoustic resonator of claim 1, wherein the material of the first electrode or the second electrode comprises any one of molybdenum, tungsten, aluminum, copper, tantalum, platinum, ruthenium, rhodium, iridium, chromium, or titanium, or a stack of the foregoing metals.
9. A method of manufacturing a thin film bulk acoustic resonator, comprising:
providing a third substrate;
forming a piezoelectric laminated structure on the third substrate, wherein the piezoelectric laminated structure comprises a second electrode layer, a piezoelectric layer and a first electrode layer which are sequentially formed on the third substrate;
forming a support layer on the piezoelectric stack structure;
forming a first cavity in the support layer, wherein the first cavity penetrates through the support layer;
forming a first groove at the bottom of the first cavity, wherein the first groove penetrates through the first electrode layer and the piezoelectric layer;
bonding a first substrate on the support layer, wherein the first substrate covers the first cavity;
removing the third substrate;
forming a dielectric layer on the exposed surface;
forming a second cavity on the dielectric layer, wherein the second cavity penetrates through the dielectric layer, and the second cavity is positioned above the first cavity;
forming a second groove at the bottom of the second cavity, wherein the second groove is positioned above the first cavity and penetrates through the second electrode layer and the piezoelectric layer, the area surrounded by the first groove and the second groove is an effective working area of the resonator, and the first groove and the second groove are connected or provided with a gap at two junctions of projection of the bottom surface of the first substrate;
and bonding a second substrate on the dielectric layer, wherein the second substrate covers the second cavity.
10. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, wherein the cross-section of the active region is polygonal in shape and any two sides of the polygon are not parallel.
11. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, wherein the sidewall of the first trench has an inclination angle of greater than 90 degrees with respect to the plane in which the second electrode is located; the inclination angle of the side wall of the second groove and the plane where the first electrode is located is larger than 90 degrees.
12. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, characterized in that the third substrate is removed by etching or mechanical polishing.
13. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, characterized in that the method of forming the first trench and the second trench comprises dry etching.
14. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, characterized in that the method of forming the first cavity or the second cavity comprises wet etching or dry etching.
15. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, further comprising forming an etch stop layer on the first electrode after forming the first electrode and before forming the support layer.
16. The method of claim 15, wherein the material of the etch stop layer comprises silicon nitride or silicon oxynitride.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910656067.3A CN112039479B (en) | 2019-07-19 | 2019-07-19 | Film bulk acoustic resonator and manufacturing method thereof |
| PCT/CN2020/099645 WO2021012916A1 (en) | 2019-07-19 | 2020-07-01 | Film bulk acoustic resonator and method for manufacturing same |
| JP2021503031A JP7130841B2 (en) | 2019-07-19 | 2020-07-01 | Thin-film bulk acoustic wave resonator and manufacturing method thereof |
| US17/199,966 US11923826B2 (en) | 2019-07-19 | 2021-03-12 | Film bulk acoustic resonator and fabrication method thereof |
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| CN201910656067.3A CN112039479B (en) | 2019-07-19 | 2019-07-19 | Film bulk acoustic resonator and manufacturing method thereof |
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| CN112039479B true CN112039479B (en) | 2023-12-22 |
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| US (1) | US11923826B2 (en) |
| JP (1) | JP7130841B2 (en) |
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| CN112820655A (en) * | 2020-12-31 | 2021-05-18 | 中芯集成电路（宁波）有限公司 | Packaging method of semiconductor device |
| CN112953447B (en) * | 2021-02-09 | 2023-08-11 | 偲百创(深圳)科技有限公司 | Resonator and electronic device |
| WO2022205214A1 (en) * | 2021-03-31 | 2022-10-06 | 华为技术有限公司 | Filter and manufacturing method therefor, and electronic device |
| KR20220166616A (en) * | 2021-06-10 | 2022-12-19 | 삼성전기주식회사 | Acoustic wave resonator package |
| CN113405946B (en) * | 2021-06-18 | 2022-08-09 | 机械工业仪器仪表综合技术经济研究所 | Micro-electromechanical resonance type viscosity sensor |
| WO2023140327A1 (en) * | 2022-01-19 | 2023-07-27 | 株式会社村田製作所 | Elastic wave device |
| CN116054775B (en) * | 2022-11-09 | 2023-08-04 | 天通瑞宏科技有限公司 | Preparation method of acoustic wave device and acoustic wave device |
| CN116318029B (en) * | 2023-05-16 | 2023-07-21 | 深圳新声半导体有限公司 | Bulk acoustic wave resonator and method for manufacturing the same |
| CN116683881A (en) * | 2023-07-27 | 2023-09-01 | 深圳新声半导体有限公司 | Preparation method and packaging method of bulk acoustic wave resonator |
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- 2019-07-19 CN CN201910656067.3A patent/CN112039479B/en active Active
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| JP2010041153A (en) * | 2008-07-31 | 2010-02-18 | Kyocera Corp | Piezoelectric resonator, and method of manufacturing the same |
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| Publication number | Publication date |
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| WO2021012916A1 (en) | 2021-01-28 |
| US20210234531A1 (en) | 2021-07-29 |
| JP7130841B2 (en) | 2022-09-05 |
| CN112039479A (en) | 2020-12-04 |
| JP2021536158A (en) | 2021-12-23 |
| US11923826B2 (en) | 2024-03-05 |
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